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Electronic parallel voltage sources exercises?

  1. Femme_physics

    Femme_physics 2,555
    Gold Member

    I'm trying to google for some but results often lead me to forum questions, theory articles, etc. Basically I'm looking for circuits questions with parallel voltage sources answers, where I am supposed to do the work to find out the solution for the current.
     
  2. jcsd
  3. I like Serena

    I like Serena 6,193
    Homework Helper

    Hi Fp! :smile:

    I'll give you a problem (found on PF).


    [​IMG]

    given this circuit find the current on R1,R2 and R3.


    Can you solve it?
     
  4. I like Serena

    I like Serena 6,193
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    And here's a second one.
    Perhaps you can start a separate thread for this problem?


    For the circuit shown below, determine the voltage for each of the
    resistors and label the values on the diagram.
    [​IMG]
     

    Attached Files:

    Last edited: Jul 7, 2011
  5. Femme_physics

    Femme_physics 2,555
    Gold Member

    Thanks, ILS! I'll take a crack at it soon :smile: ^^
     
  6. I like Serena

    I like Serena 6,193
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    [​IMG]

    [​IMG]
     

    Attached Files:

  7. Femme_physics

    Femme_physics 2,555
    Gold Member

    Also too easy :smile: I think I'll skip it. I'm really looking for one with parallel voltage sources. I've been googling but it's hard to find an exercise with answers. Do you happen to remember or have another one I can work on?
     
  8. I like Serena

    I like Serena 6,193
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    Too easy eh? I guess I have not been anticipating your phenomenal progress! :smile:

    Ok.
    How about this one?

    [​IMG]
     
  9. Femme_physics

    Femme_physics 2,555
    Gold Member

    Eep.





    Yikes.



    Looks intimidating.




    *touches her lucky item to imbue self with ILS-like powers*

    I'll give it a shot!
     
  10. I like Serena

    I like Serena 6,193
    Homework Helper

    Once the item has inspired you enough to finish the problem, I have another one here.
    I hope it's not too easy! :devil:

    [​IMG]
     
  11. Femme_physics

    Femme_physics 2,555
    Gold Member

    Uh, where are the voltage sources?
     
  12. I like Serena

    I like Serena 6,193
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    Who needs voltage sources, when you can get current sources?
    Or are you certain you won't get those?

    It seemed smart to me, to not only practice exactly the same problem over and over, but to vary it a bit and make sure you're not thrown off by some detail that should not matter.
    The method is exactly the same....
     
  13. Femme_physics

    Femme_physics 2,555
    Gold Member

    Yes, but I don't know where are they located! Shouldn't you tell me at least where are they located if not their value?
     
  14. I like Serena

    I like Serena 6,193
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    There are no voltage sources.
    Instead there are current sources that are similar.

    An (ideal) voltage source provides a constant voltage.
    An (ideal) current source provides a constant current (the voltage drop is zero).
     
    Last edited: Jul 9, 2011
  15. Femme_physics

    Femme_physics 2,555
    Gold Member

    Oh, well we haven't studied about that, I'm pretty sure it's not gonna be on the test! Should I really be trying to solve that?
     
  16. I like Serena

    I like Serena 6,193
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    Well, yeah!

    To get a perfect score, you need to be able to play with the material.
    It does not suffice that you have drilled one specific exercise over and over.
    You need to have the confidence that whatever they throw at you, you simply know it won't matter, because you know your stuff, and are not thrown off by surprises!

    That is, unless you're content with doing just well enough to pass the test.
    (But then you'll have these guys looming over you that you don't dare contradict, because you're not sure whether you know better. :wink:)

    (And if you don't do these exercises, you'll not be spending time with me! Sniff! :cry:)
     
  17. You can transform voltage and current sources interchangeably with resistors.

    If you want a big list of circuits problems I would get the Schaum's outline of Electric Circuits btw.
     
  18. Femme_physics

    Femme_physics 2,555
    Gold Member


    Well, what's the physical difference between a current source and a voltage source? Voltage source is plus and minus. A place with lower amount electrons connected to a place with greater amount of electrons....Is a current source the same?
     
  19. I like Serena

    I like Serena 6,193
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    Uh yes, in the sense that you mention it is the same.
    The physical difference is that a voltage source has a fixed voltage difference and a variable current, depending on the circuit.
    Whereas a current source generates a fixed current and a variable voltage difference, depending on the circuit.

    (Btw, I have to retract my statement that the voltage drop across a current source is zero. It isn't.)
     
  20. Femme_physics

    Femme_physics 2,555
    Gold Member

    Hmm...then do I treat a voltage source like a current source when I build my equations? Or do I discount V and build the equations?
     
  21. I like Serena

    I like Serena 6,193
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    Can I get a good morning from you? :smile:

    Start with building the equations that you think you can build.
    You should be able to apply KCL.
    Use KVL only on loops that do not contain a current source (since you won't get useful information from that).
     
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